enum_type.h File Reference

#include "platform.h"

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Macros
#define	ETL_DECLARE_ENUM_TYPE(TypeName, ValueType)
#define	ETL_ENUM_TYPE(value, name)
#define	ETL_END_ENUM_TYPE

Macro Definition Documentation

ETL_DECLARE_ENUM_TYPE

#define ETL_DECLARE_ENUM_TYPE	(		TypeName,
			ValueType )

Value:

  typedef ValueType value_type; \
    ETL_CONSTEXPR TypeName() : value(static_cast<enum_type>(value_type())) {} \
    ETL_CONSTEXPR TypeName(enum_type value_) : value(value_) {} \
  ETL_CONSTEXPR explicit TypeName(value_type value_) : value(static_cast<enum_type>(value_)) {} \
    ETL_CONSTEXPR operator value_type() const {return static_cast<value_type>(value);} \
  ETL_CONSTEXPR value_type get_value() const {return static_cast<value_type>(value);} \
  ETL_CONSTEXPR enum_type get_enum() const {return value;} \
  ETL_CONSTEXPR14 const char* c_str() const \
  { \
    switch (value) \
    {

struct CompassDirection
{
  enum enum_type
  {
    North = 0,
    South = 180,
    East  = 90,
    West  = 270
  };
 
  ETL_DECLARE_ENUM_TYPE(CompassDirection, int)
  ETL_ENUM_TYPE(North, "North")
  ETL_ENUM_TYPE(South, "South")
  ETL_ENUM_TYPE(East,  "East")
  ETL_ENUM_TYPE(West,  "West")
  ETL_END_ENUM_TYPE
};

Using the enumeration.

CompassDirection direction;          // Default construction.
 
direction = CompassDirection::North; // Assignment from an enumeration constant;
 
int value = direction;               // Implicit conversion to 'int'.
 
direction = CompassDirection(value); // Explicit conversion from 'int'.
 
direction = CompassDirection(3);     // Explicit conversion from an invalid value. This unfortunately cannot be avoided. Caveat emptor!
 
direction = value;                   // Implicit conversion from 'int'. **** Compilation error ****
 
std::cout << "Direction = " << direction.c_str(); // Prints "Direction = North"

If a conversion to a string is not required then the 'ETL_ENUM_TYPE' declaration may be omitted. In that case the c_str() function will return a "?". This will also be the case for any enumeration value that does not have an ETL_ENUM_TYPE entry.

ETL_END_ENUM_TYPE

#define ETL_END_ENUM_TYPE

Value:

      default: \
        return "?"; \
    } \
  } \
private: \
  enum_type value;

ETL_ENUM_TYPE

#define ETL_ENUM_TYPE	(		value,
			name )

Value:

      case value: \
        return name; \